1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * SNMP service broadcast connection tracking helper
5 * (c) 2011 Jiri Olsa <jolsa@redhat.com>
7 #include <linux/kernel.h>
8 #include <linux/module.h>
9 #include <linux/init.h>
12 #include <net/netfilter/nf_conntrack.h>
13 #include <net/netfilter/nf_conntrack_helper.h>
14 #include <net/netfilter/nf_conntrack_expect.h>
15 #include <linux/netfilter/nf_conntrack_snmp.h>
19 MODULE_AUTHOR("Jiri Olsa <jolsa@redhat.com>");
20 MODULE_DESCRIPTION("SNMP service broadcast connection tracking helper");
21 MODULE_LICENSE("GPL");
22 MODULE_ALIAS_NFCT_HELPER("snmp");
24 static unsigned int timeout __read_mostly
= 30;
25 module_param(timeout
, uint
, 0400);
26 MODULE_PARM_DESC(timeout
, "timeout for master connection/replies in seconds");
28 int (*nf_nat_snmp_hook
)(struct sk_buff
*skb
,
31 enum ip_conntrack_info ctinfo
);
32 EXPORT_SYMBOL_GPL(nf_nat_snmp_hook
);
34 static int snmp_conntrack_help(struct sk_buff
*skb
, unsigned int protoff
,
36 enum ip_conntrack_info ctinfo
)
38 typeof(nf_nat_snmp_hook
) nf_nat_snmp
;
40 nf_conntrack_broadcast_help(skb
, ct
, ctinfo
, timeout
);
42 nf_nat_snmp
= rcu_dereference(nf_nat_snmp_hook
);
43 if (nf_nat_snmp
&& ct
->status
& IPS_NAT_MASK
)
44 return nf_nat_snmp(skb
, protoff
, ct
, ctinfo
);
49 static struct nf_conntrack_expect_policy exp_policy
= {
53 static struct nf_conntrack_helper helper __read_mostly
= {
55 .tuple
.src
.l3num
= NFPROTO_IPV4
,
56 .tuple
.src
.u
.udp
.port
= cpu_to_be16(SNMP_PORT
),
57 .tuple
.dst
.protonum
= IPPROTO_UDP
,
59 .help
= snmp_conntrack_help
,
60 .expect_policy
= &exp_policy
,
63 static int __init
nf_conntrack_snmp_init(void)
65 exp_policy
.timeout
= timeout
;
66 return nf_conntrack_helper_register(&helper
);
69 static void __exit
nf_conntrack_snmp_fini(void)
71 nf_conntrack_helper_unregister(&helper
);
74 module_init(nf_conntrack_snmp_init
);
75 module_exit(nf_conntrack_snmp_fini
);